Apparatus for forming panels



' June 6, 1944. I J. A. MILLER 2,350,915

- APPARATUS FOR FORMING PANELS Filed April 13, 1942 2 Sheets-Sheet 1 PI.P

mvmron. JZw/v /7. MILLER.

June 1944- A. MILLER 2,350,915

APPARATUS FOR FORMING PANELS Filed April -13, 1942 2 Sheets-Sheet 2 INVENTOR.

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Patented June 6, 1944 APPARATUS FOR FORltflNG PANELS John A. Miller, De Kalb, 111., assignor to The Rudolph Wurlitzer Company, Chicago, 111., a,

corporation Application April 13, 1942, Serial No. 438,772

Claims. (Cl. 144-266) This invention relates to an apparatus for forming panels ofpliable material, such as plywood and the like.

The invention is directed to an improvement in forming plywood panels, or panels of like pliable material, to overcome the difiiculties heretofore encountered in the equal distribution of pressure between the cauls. Thus, in the use of male and female cauls for forming curved plywood panels, the maximum pressure occurs near the central portion thereof with the pressure between the cauls progressively decreasing to a negligible amount toward the sides. This is particularly true wherein the panel to be formed is of irregular curvature or shape. A further object of the invention is to improve upon the method and apparatus heretofore employed to the end that the cauls may be more economically and rapidly produced in order to form plywood panels of different and varying curvature and shape.

One feature of the invention which is directed toward the more economical production of such panels, lies in the employment of apparatus equipped with a plurality or series of separate and independent female cauls with independent pressure controls applicable about a male caul or forming die, there being provided a separately controlled female caul for each section of the curved panel capable of receiving a substantially constant pressure.

A further feature of the invention resides in the method employed in flattening out all laminae of the plywood and applying forming pressures thereto progressively from one end or edge thereof to the other.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims:

Fig. 1 is an end elevational view showing the apparatus embodying the invention in forming position. Fig. 2 is the same as Fig. 1, showing the apparatus in open position. Fig. 3 is a plan view showing the apparatus in forming position. Fig. 4 is a perspective view of the panel of irregular curvature or shape formed therein.

In the drawings there is shown, for example, a forming die or male caul pre-formed to the desired curvature or shape about which a sheet of laminated plywood is drawn, after which a plurality of individual and separable female cauls are applied progressively under pressure. The apparatus comprises a supporting base I0 having a plywood engaging and locking shoulder ll adjacent which there is provided an anchor plate I2 for securing the male caul or forming die generally indicated at l3.

Said male caul comprises a wooden block or core I of a general size and shape approaching that of the caul and which has its periphery grooved, as indicated at l5, to receive a series of transverse heating elements, which may be in the form of steam pipes l6 connected in series at one end of the caul and'through which steam from any suitable source may be passed. The forming surface of the caul l3 may be formed of a cast metal of low melting point, suchas babbitt, lead or the like, to form a liner ll of the desired exterior surface supported by the wooden core and embedding therein the heating elements l6. s

The advantages of so constructing the male caul are substantial, and permit production of male cauls of varying shapes and uses rapidly and at low cost while at the same time providing a metal surface to which heat from the heating elements is efiectively transmitted. Thus, the desired male caul may be quickly built up by forming a wooden core and a suitable wooden form between which the forming liner is cast after the pipes are in position, as more particularly set forth in my copending application Serial No. 354,972, filed August 31, 1940, entitled Heated mold form, and now issued as Patent No. 2,311,561, Feb. 16, 1943, and in my copending application Serial No. 435,668, filed March 21, 1942,

entitled Method of producing forms for molding veneer, now issued as Patent No. 2,330,371, Sept.

For drawing the plywood about the male caul there is provided a spring steel sheet 18 having one end fixedly secured to the shoulder II and the other end secured to a tension and pressure block l9; About theinale caul and spring sheet l8 there is provided aplurality of separate female cauls 20, 2| and22. Each of said female cauls is provided with a curved forming surface which conforms to the curvature of the section of the male caul toward which it is' directed. Said female cauls are preferably formed and shaped from wooden blocks with their curved surface protected by a sheet metal liner 23. The caul 20 may rest and slide upon the supporting base In and the caul 22 may be loosely supported by a pivoted head frame 24 while the caul 2! may rest loosely therebetween, or, if desired, be loosely hinged to one or the other of the cauls 20, 22.

The head frame 24 extends over the cauls and upon an upright frame 26 mounted upon the Ii adapted to normally engage and latch the head frame to resist any upward pressure thereofwhile permitting unlatching to raise said frame to caul releasing position. Said head latch is normally held in latching position by a tension spring 32 connecting it near its pivotal mounting with the lower part of the male caul. The head frame is provided with a brace 83 secured thereto and passing over the pressure block 28. Also supported upon the base there is a fixed upright pressure block 34 which bears against the spacing block 35 mounted intermediate thereof and the male caul. The pressure blocks 21 and M which are positioned on opposite sides of the male caul, are tied together by a tie rod 36.

Mounted in each of the pressure blocks above mentioned for engagement with the respective female cauls, there isprovided a plurality of pressure screws manually operable to exert pressure on said cauls progressively. Threaded through the pressure block or blocks 21 there are four pressure screws 31 each provided with a crank for rotating the same and a head engaging against the caul substantially centrally thereof. Similarly, screw threaded upon the pressure block or blocks 28 there are shown herein four pressure screws 38 provided with a crank to rotate the same to force the head of the screw against the caul 2|. Threaded through the pressure block 29 there are three pressure screws 39 provided with a crank handle for operating the same and the pressure head bearing against the caul 22. Screw threaded through the pressure block 30 there are provided three pressure screws 40 having a crank for operating the same to force the head of the screw downwardly on the upper surface of the tension and pressure block l8. Threaded in the fixed upright pressure block 34 there are provided three pressure screws ll having a crank for rotating the same to exert lateral pressure against the tension and pressure block l9.

To form the plywood panel A the male caul or forming die If is built up in the manner above described, to the inside dimensions and curvature of the desired exterior surface of the panel. With the apparatus so formed and built up, it is initially in open position, as shown in Fig. 2. In this position the plywood panel is placed over the male caul with its lower edge lying or wedged between the lower surface thereof and the shoulder H. The pivoted head frame is then moved to closed position by the handle 42 and latched in such closed position by the pivoted head latch ILasshoWninFIgJ.

The apparatus is then ready to employ the method herein described of progressively rolling and forming the panel under heat. Thus, the male caul is heated through the medium of the heating elements or steam pipes l6 and the panel ,is drawn over and about the male caul by the spring steel sheet ll through the lowering into position of the tension and pressure block is after it has been released from its supporting hook l3. Said sheet and the panel are drawn taut by the pressure exerted on block Is by the pressure screws It. The femalecaul 20 is then forced against the panel to exert lateral pressure thereon through operation of the pressure screws 31. After a predetermined pressure has been applied to this portion of the panel. screws 40 are operated to further draw the sheet thereover as the laminae of the panel are flattened out by pressure of the caul 20. Thereupon the pressure screws 38 are operated to compress the panel through that section thereof engaged by the female caul 2|. Again the screws 40 are operated to further draw the sheet 18 thereabout after the laminae of the plywood is further flattened out through pressure of the caul 2 I.

The same operation then takes place by operating the pressure screws 39 to exert pressure through the caul 22 followed by again operating the screws 40 to take up any slack thereby created in the sheet l8. This final operation of the screws 4!! draws the sheet tightly over the sharp curvature or bend immediately beyond the caul 22, thereby exerting the desired pressure thereabout. The pressure screws 4| are then operated to force the pressure block is against the remaining or end portion of the panel. The forming pressures thus applied are maintained until the panel has been completely processed, whereupon the screws are released and the apparatus opened up to permit removal of the formed panel and the placement of a new panel therein.

It will thus be observed that the method utilizing said apparatus consists essentially in first drawing the panel about the male caul by the spring sheet I 8, while the male caul is generating heat, and thereupon progressively exerting pressure from one end of the panel to the other while exerting intermittent tension on the sheet to take up slack and flatten out the laminae as the progressive pressure is applied through the independently operated female cauls.

The invention claimed is:

1. An apparatus for forming panels of irregular curvature including a male caul having an effective surface of the desired curvature, a flexible drawing member anchored at one side of said caul arranged to overlie a panel positionedthereon, a plurality of separate and independently operated female cauls positioned about the curved surface of'said male caul, each conforming to an adjacent section of its curvature respectively, a positively actuated pressure member operable to force said drawing member against the panel under pressure, and means for independently forcing said female cauls into pressure exerting position progressively from one side of the panel to the other about the curved surface of the male caul.

2. An apparatus for forming panels of irregular curvature including a male caul having an effective surface of the desired curvature, a flexible drawing member anchored at one side of said caul arranged to overlie a panel positioned thereon, a plurality of separate and independently operated female cauls positioned about the curved surface of said male caul, each conforming to an adjacent section of its curvature respectively, and a series of pressure. members independently engageable with said drawing membervand female cauls progressively operable to force said cauls into pressure exerting position about the curved surface of said mal caul and cause said member to further draw the panel about the male caul following the pressure exerted thereagainst by each successive female caul.

3. An apparatus for forming panels of irregular curvature including a male caul having an effective surface of the desired curvature, a flexible drawing member anchored at one side of said caul arranged to overlie a panel positioned thereon, a plurality of separate and independently operated female cauls positioned about'the curved surface of said male caul, each conforming to sure screws engageable with the respective female cauls progressively operable to conform the panel by a series of fixed pressures about the corresponding curved sections of the male caul and maintain said panel thereabout under compression.

4. An apparatus for forming panels of irregular curvature including a frame having a supporting base and a hinged head member, a releasable latch engageable with said head member for looking it in operative position, a male caul having an effective surface of the desired curvature secured on said base, a spring steel sheet anchored at one side of said caul arranged to overlie a panel positioned thereon, a pressure screw operable in said frame connected with the free end of said sheet adapted to forcibly draw it against said panel and caul, a plurality of separate and independently operable female cauls positioned about said male caul, each conforming to a section of its curvature, and pressure screws independently operably mounted in ,said frame engageable withthe respective female cauls to .force the panel about their respective curved sections of the male caul and maintain it in the other with interposed applications of the drawing force exerted thereon by said flexible sheet.

5. An apparatus for forming panels of irregular curvature including a frame having a supporting base and a hinged head member, a releasable latch engageable with said head member for looking it in operative position while permitting it to be open to replace a panel to be formed,

a male caul secured on said base comprising a wooden core having peripheral recesses formed thereabout, heating elements extending into said recesses, a forming surface about said core formed of low melting point metal cast thereabout with an exposed surface of the desired curvature and with said heating elements embedded therein, a spring steel sheet anchored at one side of said caul arranged to overlie the panel positioned thereover, a pressure screw operable in said frame engageable with the free end of said sheet adapted to forcibly draw it against said panel and caul, a plurality of sepa rate and independently operable female cauls mounted on said frame and positioned about said compression, whereby said female cauls may be progressively set from one end of the panel to male caul; each conforming to a section of its curvature, and pressure screws mounted in said frame engageable with the respective female cauls and independently operable to progressively set said cauls in pressure exertlng'position from one end of the panel to the other followinginterposed applications of the drawing force exerted on said flexible sheet.

JOHN A. MIILER. 

